An extensive program of quasi-static mechanical property tests was conducted to characterize the mechanical behavior of type N and type S mortars under various stress and strain boundary conditions to decide which mortar to use in the construction of triple-brick and brick-over-block walls. The material characterization effort consisted of hydrostatic compression, unconfined compression, triaxial compression, direct pull, reduced triaxial extension, and uniaxial strain tests. The results from all of the quasi-static tests provided the mechanical properties required for determining which mortar to use in the construction of target walls for projectile perforation experiments as well as the constitutive model coefficients for numerical simulations of these experiments. This paper provides a summary of the mechanical property test results obtained for type N and type S mortars and the rational for using type S mortar in the construction of triple-brick and brick-over-block walls.